Thank you for the report
You were not the first reporting this behaviour.
I think i will not fix that any soon, but here is a brief explaination how the sitemaster table works.
If you update a site and reach 100% you will get an entry in the sitemaster table, containing data from your first linking and your last update.
It will insert your first percent solved and date of the first linking, as well as date when you first reached 100%.
By the way, unlink and link again will not affect the 1st link values.
Now, of course it most likely will happen that a site will add a challenge, so your percent-solved drops below 100% again.
I decided to not cleanup these rows, as usually you really earned your sitemaster entry already.
I think i could delete rows that drop below 90% (or similar values)... but i will have to check that out first, also i am not sure if i`d like that.
If more people think i am doing it the wrong way, vote this post "thumbs down" or post your opinion